Abstract
Kinetics of homogeneous nucleation and growth of copper precipitates under electron irradiation of FeCu
alloys at concentrations
from 0.06 to 0.4 at.% and temperatures
from 290 to 450
C is studied using the kinetic Monte Carlo (KMC) simulations and the statistical theory of nucleation (STN). The conventional assumption about the similarity of mechanisms of precipitation under electron irradiation and during thermal ageing is adopted. The earlier-developed
model of interactions in Fe–Cu alloys is used for both the KMC simulations and the STN calculations. Values of the nucleation barrier
and the prefactor
in the Zeldovich–Volmer relation for the nucleation rate
are calculated for a number of concentrations and temperatures. For the dilute alloys with
, the STN and the KMC results for the nucleation barrier
do virtually coincide with each other, which seems to confirm a high reliability of the STN for this problem. The STN calculations are also used to estimate the temperature dependencies of concentrations which correspond to the homogeneous or the heterogeneous precipitation limit,
and
, and both dependencies are found to be rather sharp.
Acknowledgments
We are very grateful to V. Yu. Dobretsov for his help in the computations using the STN, as well as to A. Barbu and K. Yu. Khromov, for fruitful discussions. The work was supported by the Russian Fund of Basic Research (grant No. 12-02-00093); by the fund for support of leading scientific schools of Russia (grant No. NS-215.2012.2); and by the programme of Russian university scientific potential development (grant No. 2.1.1/4540).